While Type-2 diabetes is associated with a 20 percent greater risk of dementia and depression alone was associated with an 83 percent greater risk, having both depression and Type-2 diabetes was associated with a 117 percent greater risk, the study indicated.The risk for dementia appeared to be even greater among those study participants younger than 65.

The authors found that during the study period, 2.4 percent of individuals (59,663 people) developed dementia and the average age at diagnosis was nearly 81 years.Of those individuals who developed dementia, 15,729 people (26.4 percent) had depression alone and 6,466 (10.8 percent) had Type-2 diabetes alone, while 4,022 (6.7 percent) had both conditions.